Tuyere for blowing gas into a melting furnace

ABSTRACT

A tuyere for blowing gas into a melting furnace, in which the cooling chamber in the body of the tuyere is divided, by means of a partition wall, into a front cooling chamber and a back cooling chamber, the front cooling chamber comprises a screw-type pipe line surrounding the head part of the tuyere, and both cooling chambers are connected respectively to different cooling pipe lines independently.

United States Patent [1 1 Horio et a1.

[ Dec. 16, 1975 TUYERE FOR BLOWING GAS INTO A MELTING FURNACE Assignee: Nippon Steel Corporation, Tokyo,

Japan Filed: Jan. 10, 1974 Appl. No.: 432,203

US. Cl. 266/41; 122/66; 110/1825 Int. Cl. C213 7/16 Field of Search 110/1825; 122/66;

References Cited UNITED STATES PATENTS 8/1900 Thomas et al. 266/41 2,058,577 10/1936 Ebner et al. 122/66 2,145,649 l/1939 Fox 122/66 2,735,409 2/1956 Aurin et al r 122/66 3,052,219 9/1962 Haack et a1 266/41 3,712,602 l/l973 Brown et al. 266/41 3,826,479 7/1974 lkegawa 266/41 Primary Examiner-Gerald A. Dost Attorney, Agent, or FirmToren, McGeady and Stanger [57 ABSTRACT A tuyere for .blowing gas into a melting furnace, in which the cooling chamber in the body of the tuyere 18 divided, by means of a partition wall, into a front cooling chamber and a back cooling chamber, the front cooling chamber comprises a screw-type pipe lme surrounding the head part of the tuyere, and both coolmg chambers are connected respectively to different cooling pipe lines independently.

6 Claims, 4 Drawing Figures US. Patent Dec.16,1975 Sheet10f2 3,926,1'7

US. Patent Dec. 16, 1975 Sheet 2 of2 3,926,417

E E Z Z x Z: :5: t; m w m my 0 Q Q H a QQQQQQQQw QQQQQ mw QMMQR gm 1m Eh Q m. 5 g $3 mm 0 an Qm gm 6% a0 Q Ma Q V @QE R$E Ewfikk HQE u W mw TUYERE FOR BLOWING GAS INTO AMELTING FURNACE the tuyere for blowing gas into a high-temperature l melting furnace is usually projected far into the furnace, for instance, in the case of blast furnace about 400 mm from the wall. Accordingly, the tuyere is broken frequently due to the severe operation condition, and its body is generally made of high-quality copper material and cooled with circulating water. There have also been many fruitless proposals in the construction and cooling means of the tuyere.

For example, according to a Japanese Utility Model Publication Sho 4l -l3054, the cooling chamber is divided into a front cooling chamber and a reartcooling chamber and a cooling mechanism is provided separately so that even when the front cooling chamber is destroyed the tuyere life is maintained with the cooling in the rear cooling chamber. However, still in this prior art there are difficulties such that the top end is not cooled sufficiently, and hen the pressure of water supply is increased to enhance the cooling effect, the water circulates only in a turbulent flow, so that a high'flow speed can not be obtained and the tuyere is not protected from damage.

The object of the present invention is to offer an excellent and durable tuyere. The present invention is a tuyere for blowing air or other gases into a high-temperature melting furnace, particularly into a blast furnace, in which the cooling chamber in the body of the tuyere is divided, by means of a partition wall, into a front cooling chamber and a back cooling chamber, said front cooling chamber comprises a screw-type pipe line surrounding the head part of the tuyere, and both cooling chambers are connected respectively to different cooling pipe lines independently. It is preferable that said screw-type cooling pipe line is comparatively short in order to pass cooling water speedily therethrough.

In this invention, it is possible to pass a high-speed cooling water in the front cooling chamber, and accordingly, the tuyere can stand remarkably against melting due to the adhesion of the high-temperature melt in the furnace, and its life can be prolonged remarkably as compared with a conventional watercooled tuyere. Moreover, even when the front chamber is damaged by melting, the tuyere can be used continuously by cutting the cooling water supply to the front chamber at once and by cooling with the use of only the back chamber, and thus, the breakage of the tuyere does not always connect directly with the cessation of operation.

An example of the embodiment will be described in detail according to the drawings. In the drawings,

FIG. 1 shows the longitudinal section of the present inventive tuyere,

FIG. 2 is its rear view,

FIG. 3 is a cross-sectional view at A A in FIG. 1,,

In FIG. I, l is the body of the tuyere, 2 is the front cooling chamber, 4 is the back cooling chamber, 3 is a partition wall to divide the front cooling chamber 2 and the back cooling chamber 4, 5- is an inlet of supply water to the back-cooling chamber 4, 6 is a water supply-pipe line to the front cooling chamber and'7 is its flange. The body'of the tuyere includes an annular inner wall 11 and an annular outer wall 12 laterally enclosing ancl'spaced radially outwardly from the inner wall. End walls 13, 14 extend across the respective ends of the inner and outer -walls forming a closed space.

The partitionwall 3 divides the closed space into the front cooling chamber 2 and the back cooling-chamber 4. The front cooling chamber 2 forms a screw-type pipe line that is a flow passage with a plurality of helical turns, by means of a partition wall 2a. In FIG. 2, a water discharge pipe 8 is connected to the front cooling chamber 2, and-9 is provided for an outlet of cooling water from the back cooling chamber 4. Other symbols are the same as in FIG. I. In FIG. 3, 2a is a partition wall to construct the screw-type cooling pipe line in the front cooling chamber 2, which has, in this instance, two turns. 3 is, as already mentioned, the partition wall to divide the two cooling chambers, 6 is the water supply pipe, 7 is its flange, 8 is the water discharge pipe from the "front cooling chamber 2 and is its flange. The dimensions of this tuyere are: the opening diameter at the top end is 160 mm, the outer diameter thereat is 310 mm, the opening diameter at the back end is 210 mm, the outer diameter thereat is 390 mm, and the position of the partition wall 3 is 100 mm from the top end. The length of the tuyere is 475 mm.

Cooling water supplied from the water supply pipe 6 circulates through the front cooling chamber 2 comprising a screw-type or helically formed pipe line in the direction as shown with an arrow in FIG. 3, and is dis- 7 charged through the water' discharge pipe 8.-Cooling water to the back cooling chamber is supplied from another water supply line (not shown) through the cooling water inlet 5, and is discharged throughthe water outlet 9.

The result of practical operations using this tuyere were quite satisfactory. The speed of cooling water passing through the screw-type pipe line surrounding the head part of the tuyere could be raised as fast as 5 2O m/sec. It was confirmed that the life of the head part was more than twice as long as the life of a conv entional tuyere with one cooling chamber construction. When the wall of the front cooling chamber 2 was broken, the water supply pipe 6 to the front chamber was closed at once, and the tuyere could be used continuously by cooling with the use of only the back cooling chamber 4. Thus, the tuyere exchange operation could be postponed until the time of the regular cessation of operation. It wasobserved that the higher the speed of cooling water through the front cooling chamber, the smaller the damage due to melting.

FIG. 4 shows damage of the present tuyere used in a blast furnace and decrease in production of pig iron in comparison with that of a conventional single-chambered tuyere. It is clear from FIG. 4 that the damage of the present tuyere is very little and the decrease in pig iron production is almost zero during the testing period.

In this invention, it is preferable, as already mentioned, that the screw-type cooling pipe line constructing the front cooling chamber 2 is comparatively short. The front cooling chamber in the above example comprises a screw-type pipe line with two turns. and an excellent result is obtained. However, three or four turns are also suitable. It is desirous further that the supply and discharge pipe lines 6 and 8 for the front cooling chamber 2 pass through the interior of the back cooling chamber 4. It is important thereby that the resistance against the cooling water flow is possibly small. Therefore, it is desirous that both cooling pipe lines 6 and 8 are as small as possible in the range that does not injure the necessary water supply. It is also preferable that both cooling pipes 6 and 8 are of flat type, and the same is true for the screw-type pipe constructing the front cooling chamber.

What is claimed is:

l. A tuyere for blowing gas into a melting furnace comprising an annular inner wall, an annular outer wall laterally enclosing and spaced radially outwardly from said inner wall, a first end wall extending between said inner and outer walls at one end thereof and a second end wall extending between the opposite ends of said inner and outer walls for forming a closed space there between, a first partition wall located within the closed space and extending radially between said inner and outer walls transversely of the axis thereof for dividing the closed space into a front cooling chamber adjacent said first end wall and a back cooling chamber extending between said first partition wall and said second wall, wherein the improvement comprises a helically arranged second partition wall located within said front cooling chamber and extending between said inner and outer walls transversely of the axis of said inner and outer walls and forming a flow passage with a plurality of helical turns extending between said first end wall and said first partition wall, said flow passage having a dimension transversely of the axial direction of said inner and outer walls equal to the dimension between said inner and outer walls for the full extent of said flow passage from said first end wall to said first partition wall, first conduit means connected to said front cooling chamber for circulating a cooling liquid therethrough, second conduit means independent of said first conduit means and connected to said back cooling chamber for circulating a cooling liquid therethrough and said first conduit means includes a supply conduit and a discharge conduit with said supply conduit extending from said second end wall through said back cooling chamber, said first partition wall and the turns of said flow passage closer to said first partition wall and opening into the turn of said flow passage closest to said first end wall, and said discharge conduit extending from said second end wall through said back cooling chamber and said first partition wall and opening into the turn of said flow passage closest to said first partition wall.

2. A tuyere, as set forth in claim 1, wherein said flow passage in said front cooling chamber consists of four helical turns.

3. A tuyere, as set forth in claim 1, wherein said supply and discharge conduits are formed of a pipe of the flattened type.

4. A tuyere, as set forth in claim 1, wherein the di mension between said first end wall and said first partition wall is approximately 1/5 of the dimension between said first and second end walls.

5. A tuyere, as set forth in claim 1, wherein the dimension of said tuyere between said first and second end walls is 475mm and the dimension of said first partition wall from said first end wall is mm.

6. The tuyere, as set forth in claim 5, wherein at said first end wall the inside diameter of said inner wall is mm and the outside diameter of said outer wall is 310mm and at said second end wall the inside diameter of said inner wall is 210mm and the outside diameter of said outer wall is 390mm. 

1. A tuyere for blowing gas into a melting furnace comprising an annular inner wall, an annular outer wall laterally enclosing and spaced radially outwardly from said inner wall, a first end wall extending between said inner and outer walls at one end thereof and a second end wall extending between the opposite ends of said inner and outer walls for forming a closed space therebetween, a first partition wall located within the closed space and extending radially between said inner and outer walls transversely of the axis thereof for dividing the closed space into a front cooling chamber adjacent said first end wall and a back cooling chamber extending between said first partition wall and said second wall, wherein the improvement comprises a helically arranged second partition wall located within said front cooling chamber and extending between said inner and outer walls transversely of the axis of said inner and outer walls and forming a flow passage with a plurality of helical turns extending between said first end wall and said first partition wall, said flow passage having a dimension transversely of the axial direction of said inner and outer walls equal to the dimension between said inner and outer walls for the full extent of said flow passage from said first end wall to said first partition wall, first conduit means connected to said front cooling chamber for circulating a cooling liquid therethrough, second conduit means independent of said first conduit means and connected to said back cooling chamber for circulating a cooling liquid therethrough and said first conduit means includes a supply conduit and a discharge conduit with said supply conduit extending from said second end wall through said back cooling chamber, said first partition wall and the turns of said flow passage closer to said first partition wall and opening into the turn of said flow passage closest to said first end wall, and said discharge conduit extending from said second end wall through said back cooling chamber and said first partition wall and opening into the turn of said flow passage closest to said first partition wall.
 2. A tuyere, as set forth in claim 1, wherein said flow passage in said front cooling chamber consists of four helical turns.
 3. A tuyere, as set forth in claim 1, wherein said supply and discharge conduits are formed of a pipe of the flattened type.
 4. A tuyere, as set forth in claim 1, wherein the dimension between said first end wall and said first partition wall is approximately 1/5 of the dimension between said first and second end walls.
 5. A tuyere, as set forth in claim 1, wherein the dimension of said tuyere between said first and second end walls is 475mm and the dimension of said first partition wall from said first end wall is 100mm.
 6. The tuyere, as set forth in claim 5, wherein at said first end wall the inside diameter of said inner wall is 160mm and the outside diameter of said outer wall is 310mm and at said second end wall the inside diameter of said inner wall is 210mm and the outside diameter of said outer wall is 390mm. 